When I try running the game I get sound and can click around and hear movement, etc. but there is no video/image at all, just a black screen.

I have an ATI Radeon 9600 video card with updated drivers and my comp. meets or exceeds everything else for the Recommended Requirements.

If anyone has an idea of what the problem is, I'd love the help. Knowing me it's something really stupid. My Sims 2 game is running fine, however, so I'm at a loss.

Thanks for any help!

Hit the ESC key and if you can see anything, try setting your graphics settings lower.
Make sure your monitor's plugged in the electric outlet and/or your computer because I'm just SURE you tripped over it between starting Psychonauts and the opening screen.
Read the FAQs and tech support to make sure there are no known conflicts w/your video card.
Disable other graphics intensive stuff in the background. No you should NOT play Sims 2, Spore, Oblivion, AND Psychonauts simultaneously.
Call Tim Schafer and George Lucas until their ears bleed. ;)